This proposal describes a five year training program for an academic career in cancer health services and comparative effectiveness research with an emphasis on urologic oncology and radiotherapy. I am an Assistant Professor of Radiation Oncology, a member of the Abramson Cancer Center and a Senior Fellow at the Leonard Davis Institute of Health Economics at the University of Pennsylvania. Clinically, I specialize in the treatment of prostate cancer (PCa). The unifying theme of my research is to generate evidence needed to support my patients' treatment decisions, thereby addressing the essential purpose of comparative effectiveness research (CER). I have completed an NCI F32 mentored research fellowship and now will expand my scientific skills through additional training in state-of-the-art statistical and econometric methods to estimate causal association in observational comparative effectiveness studies and decision-analytic approaches to prioritizing research designs. My long-term goal is to develop a career as an independent, grant-funded physician-investigator focused on advancing cancer comparative effectiveness research. The career development program outlined in this application contains formal mentorship, didactic coursework, and seminars structured around three methodological areas: 1) econometrics and decision analysis; 2) biostatistics for causal inference; and 3) cancer comparative effectiveness. I have assembled an interdisciplinary team of scientists at the University of Pennsylvania who are highly committed to my career development and will provide the expertise required to complete this proposal. The mentorship team will be directed by Katrina Armstrong, MD, MSCE. I will enroll in the Masters of Science Program in Health Policy Research, designed to prepare graduates for independent careers in health services research and jointly sponsored by the Leonard Davis Institute of Health Economics and the Robert Wood Johnson Clinical Scholars Program. Coursework will include instruction in econometrics/causal inference, decision analysis, value-of-information techniques, and clinical trials. These didactic courses will be complemented by independent study, seminars and small group sessions attended by an interdisciplinary group of health services researchers, economists, biostatisticians, epidemiologists, and physicians. The overall research goal of this Career Development Award is to examine the contribution of observational studies to the evidence gaps in external beam radiotherapy (EBRT) treatment for PCa. I will start by comparing results from an observational study to that of a clinical trial for question where randomized evidence is available, but will add evidence as to the relative effectiveness of EBRT across important subgroups in this population. I will then conduct two observational studies of EBRT, one focused on mortality and the other on morbidity, addressing questions for which there is no randomized evidence. Finally, with an interest in focusing the limited resources available for large studies on the evidence gaps of greatest value, I will incorporate these estimates into innovative value-of-information (VOI) models to explore the optimal research design for a future study of proton beam therapy (PBT) for PCa. The primary data source for this research is the Surveillance, Epidemiology and End Results (SEER)-Medicare database, a population-based source of information about patients 65 years and older with cancer. Based on our preliminary work, we estimate that the analytic cohorts will include a combined 111,000 patients with non-metastatic PCa diagnosed between 1995 and 2007, all followed through 2009. The secondary data source will be the National Cancer Data Base (NCDB), in which we will explore outcomes in men under 65 years of age. The scientific community at the University of Pennsylvania is outstanding and will provide the necessary resources to support my career development and the aims of this research proposal. The resources of the Center for Clinical Epidemiology and Biostatistics, the Leonard Davis Institute of Health Economics, the Department of General Internal Medicine, and the Department of Radiation Oncology provide a unique intellectual environment in which to train in innovative research methods for comparative effectiveness. These collaborations help to deepen understanding of the practical effects of clinical and policy decisions and ensure multiple viewpoints and perspectives are incorporated into health services research. Over 1.1 million men will be diagnosed with PCa in the next five years, the vast majority with localized disease. There are daunting gaps in evidence about the effectiveness of EBRT treatments. With PCa costs exceeding $12 billion per year and growing PCa mortality and morbidity as the US population ages, PCa comparative effectiveness research has the potential to impact public health. Thus, this proposal has strong clinical relevance. Through this award, I will leverage important new skills in advanced health services research methods to become an independent, grant-funded physician-scientist.